1. Field of the Invention
This invention relates to a pneumatic tire, and more particularly to a pneumatic tire for off-road vehicles, such as recreational vehicles utilizing 4-wheel drive on rough terrain.
2. General Background
Pneumatic tires used for off road recreational vehicles are susceptible to side wall cuts and cracks on the outer surface of the tire due to rocks, stumps, etc., usually encountered in off-road driving. Such off-road driving often subjects the vehicle and its tires to destructive conditions which brutalizes the tires, such as frequent bogs which subject the tire to high heat and casing cord breaking stresses due to pry bars, etc., being forced into contact with the spinning wheel. Mud adhering to the tire is also a problem. When mud builds up on the vehicle tire and packs the tire well, it can cause skidding, steering problems and increase heat on the tire. Such tires must have heavy outer layers of rubber to prevent breaking the tire cording and belting members and provide excellent traction, including good side wall adhesion in bog conditions. Further, when such vehicles return to paved or hard packed roads, it is essential that the tires be self-cleaning and be capable of running at highway speeds without wiggle, bounce or high noise factor. Several types of off-road recreational vehicle tires have been developed which address the need for aggressive traction, some of which are disclosed by my U.S. design patents D383426, D261257, D308038, D345950 and D358792. Others have disclosed reinforced or protected side wails and double caisson cores such as disclosed by U.S. Pat. Nos. 3,825,052, 4,043,372, and 4,319,618. However, today's all terrain vehicle (ATV) and recreational vehicle (RV) markets are requiring more than off road performance. Many ATV and RV owners are looking for styling which produces a quite smooth ride on road surfaces, reduces rolling resistance on paved roads thus improving fuel mileage, provides good tread wear at highway speeds and contributes to the overall appearance of the vehicle at an economical cost.